Chain cutter for sewing machines



April 26, i932. F. mz 1,855,301

CHAIN CUTTER FOR SEWING MACHINES Filed Dec. 4, 1928 o /o f4 115 '/jal Patented Apr. 26, 1932 UNITED STATES PATENT OFFICE FRIEDRICH LUTZ, OFSTUTTG'ART, GERMANY, ASSIGNOR TO UNION SPECIAL MASCHI- articles.

NENFABRIK, G. IVI. B. H.,

or STUTTGART, GERMANY CHAIN CUTTER-*FOR STEHJNGT' MACHINES i Application filed December 4, 1928, Serial No. 323,617, and in Germany September 21, 1928.

In my copending application Serial No. 315,464, filed October 27, 1928, there is shown and described a chain cutter for cutting the enchained thread loops between stitched The chain cutter is located at the rear of the presser foot and includes a lower stationary knife and an upper movable knife. The upper movable knife is raised to inoperative position while the article is passing between the chain cutters and when the enchained thread loops are betweenthe severing devices they may be operated to sever the enchained thread loops.

`The present invention has to do with a device of the above type and is directed particularly to the manner of feeding the enchained thread loops between the severing devices. i An object 'of the invention is to provide a means for feeding the enchained thread loops between stitched articles which will positively pass the enchained thread loops between the severing devices and without any danger of the end of the enchained thread loops striking the stationary severing device or the throat plate and becoming `deflected from its proper path of movement.

A further object of the invention is to provide a device of the above character wherein the throat plate directly in front of the severing devices is slotted and the feed dog is provided with an auxiliary feeding section which passes `through said slot and engages the enchained thread loops and moves in theslot to a pointclose to the severing devices so as to raise and carry the enchained thread loops between said severing devices.

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed. v

In the drawings which show by way of illustration onev embodiment of the invention Fig. 1 is a plan view showing the throat plate, the feed dog sections, the lower severing device, the needle, and in broken lines the upper severing-device with the feed dog at the front end of its stroke.

` Fig. 2 is a view similar to Fig. 1, but showing the feed dogat the rear end of its stroke.

Fig. 3 is a plan view of the throat plate.

Fig. l is a vertical sectional view through the throat plate, a portion of the feed dog, a portion of the lower severing device, and a portion of the auxiliary presser foot'which cooperates with the feeding section shown, the feeding section being at the forward end of its stroke.

Fig. 5 is a similar view, but showing the feeding section at the rear end of its stroke. y

Fig. 6 is a transverse sectional view showingpniore or less diagrammatically the feed through the throat plate, the presserv foot,

and the enchainedthread loops positioned beneath the auxiliary presser foot.

The invention is directed to a device for secvering the enchained thread loops between stitched articles, and more particularly the means for feeding the enchained thread loops so as to insure that they will be properly presented to the severing devices for Ythe action of the severing devices thereon. The severing devices are locatedV in rear of the presser foot and include a. stationary cutter and ai movable cutter which may be actuated in any way but preferably by means vcontrolled by the passing stitched articles. The enchained thread loops are fed between stitched articles by the cooperative action of auxiliary section of the presser foot. The

throat plate 1s provided with a slotdirectly in front of the severing devices and this auxiliary feeding section of the feed dog works in this slot and moves from a point well in front of the severingdevices to a point close up to the lower stationary severing device. The feed dog moves upward to apoint above the plane of the. lower. severing device and, therefore, when the enchained thread loops are engaged by this auxiliary section of the feed dog the enchainedv thread loops will. be positively raised and carried rearwardlyV between the severing devices. This insures that the end of the enchained thread loops cannot drop into against the parts of the-throat plate or the severing devices, and thus be deflected out of its proper course of travel.

Referring more in detail to the drawings, the invention is shown as embodied in a mathefeed slot or Vin any way strike i chine having a throat plate 1. This throat plate is provided with slots 2, 2, for the main outer sections 3, 3 of the main feed dog. The throat plate is also provided with a needle opening 4 and a needle 5 reciprocate in this opening. The severing devices for severing the enchained thread loops-include a lower stationary .cutting device 6V and an upper movable cutting device 7. This upper movable cutting device 7 is preferably mounted in the manner shown in my copending application above referred to and may be actuated in any desired way but preferably by means controlled by the passing stitched articles so that the severing devices are brought into action for severing the enchained thread loops between the stitched articles. These severing devices opera-te through an opening 8 in the throat plate. v

The throat plate is provided with a depression 9 directly in rear ofthe severing devices. The throat plate is slotted directly in front o-f the severing device 6 as indicated at 10 in the drawings. The main feed dog is provided with an auxiliary feeding section formed in three parts, a central part and two parts which are parallel therewith and located slightly further in advance on the main feed cated at 11 in the drawings and this auxiliary feeding section works in the slot 10. The two parts of the auxiliary section of the feed dog are located at 12, 12 and these parts operate in slots 13, 13 formed in the throat plate 1. Between the slot 10 and the slots 13, 13 are two bridging portions 14, 14. rThe enchained thread loops are indicated at 15 in the draw* `1n s.

fis clearly shown in Fig. 6, the enchained thread loops have sufficient body so as to overlie laterally the slot 10 andrest on the bridging portions 14, 14. These bridging portions extend all the way along the slot 10 and to the lower severing device 6. Directly in front of the slot 10 the throat plate is provided with a toothed section 16.

The presser foot includes two main sections 17, 17 and an auxiliary v section 18. These parts are of the construction shown in my copending application and detailed description thereof is not thought necessary. The auxiliary part 18 is yieldingly pressed downwardly toward the throat plate. When an article to be stitched is passing beneath the presser foot, this auxiliary section will take a position with its lower face substantially flush with the lower face of the main section of the presser foot. When, however, the stitched article passes from beneath the presser foot, then the main sections of the presser foot will move down onto the main sections of the feed dog and the throat plate and the auxiliary section of the presser foot will move down onto the enchained thread loops and holdsaid enchained thread loops dog. The central auxiliary part is indieither pressed against the throat plate or against the central auxiliary section of the feed dog. This central auxiliary section of the feed dog moves from' a point at the front end of the slot 10 (see Fig. 4) to a point at the rear end of said slot and during this movement the enchained thread loops are clamped against the bottom of the auxiliary section of the presser foot and moved along the same so that they are raised and positively carried over the lower severing de- Vice 6.

The toothed portion 16 on the throat plate cooperates with the auxiliary section of the presser foot in holding the enchained thread loops during the severing of the same as clearly shown in Fig. 5.

It will be apparent from the above description that the enchained thread loops are in turn supported by the bridging portions of the throat plate and the auxiliary section of the feed dog and are fed positively rearwardly between the severing devices and there is no chance for the end of the enchained thread loops striking the end of the feed slot in the throat plate or the lower severing device or in any other way being deflected from its proper course of movement between said severing devices.

It is obvious that minor changes in the details of construction and the arrangement of the parts may be made without departing from the spirit of the invention as set forth in the appended claims.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent, is

1. A sewing machine including in combination a throat plate, severing devices for severing the enchained thread loops, a presser foot, an auxiliary presser foot section on said presser foot disposed in front of said sever` ing devices and a feed dog provided with a feeding section opposed by said auxiliary presser foot section and movable on its feed stroke to a point immediately adjacent said severing devices for feeding the enchained thread loops between said severing devices.

2. A sewing machine including in combination severing devices for severing enchained thread loops, a throat plate having 'an opening for said severing devices and openings for feeding sections of a feed dog, one of said openings being relatively narrow and located centrally of the throat plate and leading into the opening for the severing devices, a feed dog having a central auxiliary feeding section operating in said central opening and in a path terminating close to the severing devices, a presser foot having an auxiliary section cooperating with said auxiliary section of the Vfeed dog, whereby .the enchained thread loops vvare clamped by the feed dog against said auxiliary section and positively carried between the severing devices.

3. A sewing machine including in combination -severing devices for severing enchained thread loops, a throat plate having an opening for said severing devices and openings for feeding sections of a feed dog, one of said openings being relatively narrow and located centrally of the throat plate and leading into the opening for the severing devices, a feed dog having a central auxiliary feeding section operating in said central opening and in a path terminating close to the severing devices, a presser foot having an auxiliary section cooperating with said auxiliary section of the feed dog, whereby the enchained thread loops are clamped by the feed dog against said auxiliary section and positively carried between the severing devices, said throat plate having a toothed portion at the front end of said central opening cooperating with said auxiliary section of the presser foot for the clamping of the enchained thread loops during the severing thereof.

Il. A sewing machine including in combination severing devices for severing enchained thread loops, a throat plate having an opening for said severing devices and an opening for a needle and also a slot centrally of the throat plate in line with the needle and extending into the opening for the severing devices, said slot being relatively narrow so as to provide supporting por- .i tions for the enchained thread loops along the side of said slot, a feed dog having an auxiliary feeding section operating in said slot, a presser foot having an auxiliary section cooperating with the auxiliary section of the feed dog, said feed dog having a path of movement terminating substantially at the rear end of said slot whereby the enchained thread loops may be clamped thereby against the auxiliary section of the presser foot and carried between the severing devices.

5. A sewing machine including in combination severing devices for severing enchained thread loops, athroat plate having an opening for said severing devices andan opening for a needle and also a slot centrally of the throat plate in line with the needle and extending into the opening for the severing devices, said slot being relatively narrow so as to provide supporting portions for the enchained thread loops along the side of said slot, a feed dog having an auxiliary feeding section operating in said slot, a presser foot having an auxiliary section cooperating with the auxiliary section of the feed dog, said feed dog having a path of movement terminating substantially at the rear end of said slot whereby the enchained thread loops may be clamped thereby against the auxiliary section of the presser foot and carried between the severing devices, said throat plate having slots disposed alongside of said central slot and spaced therefrom, and said feed dog having feeding sections operating in said last-named slots.

6. A sewing machine including in combination severing devices for severing enchained thread loops, a throat plate having an opening for said severing devices and an opening for a needle and also a slot centrally of the throat plate in line with the needle and extending into the opening for the severing devices, said slot being relatively narrow so as to provide supporting portions for the enchained thread loops along the side of said slot, a feed dog having an auxiliary feeding section operating in said slot, a presser foot having an auxiliary section cooperating with the auxiliary section of the feed dog, said feed dog having a path of movement terminating substantially at the rear end of said slot whereby the enchained thread loops may be clamped thereby against the auxiliary section of the presser foot and carried between the severing devices, said'throat plate having a toothed section between the needle opening and the front end of said slot for the auxiliary section of the feed dog for clamping the enchained thread loops during the severing thereof.

In testimony whereof, I afIix my signature.

FRIEDRICH LUTZ. 

